It is known that ankle prostheses can be used to restore a certain amount of freedom of movement to an ankle joint, after the ankle has been damaged due to injury or to disease.
In particular, it is known that an ankle prosthesis can be implanted that comprises a talar implant, a tibial implant, and an intermediate implant interposed between said tibial implant and said talar implant for the purpose of imparting mobility to the ankle.
Depending on the treatment that is to be used on the patient, and also depending on the applicable regulatory requirements, it is possible either to allow the intermediate implant considerable freedom of movement relative to the tibial implant, e.g. by placing it in free planar abutment thereagainst, or, conversely, to hold said intermediate implant stationary against the tibial implant.
Unfortunately, restraining the intermediate implant relative to the tibial implant can cause considerable mechanical stresses to appear while the prosthesis is under load, in particular during walking, and such stresses can cause premature wear or indeed irreversible damage to the implants, or can cause discomfort to the patient.
That is why, in order to adapt such prostheses to match the anatomy of the treated patient, adjustment means have been devised for making it possible to modify the assembly configuration of the intermediate implant relative to the tibial implant.
Although such prostheses are generally satisfactory, they can however suffer from certain drawbacks.
The adjustment possibilities offered by prior art prostheses can be relatively limited, which does not always enable the overall arrangement of the prosthesis to coincide with the natural anatomy of the patient.
In addition, known adjustment methods generally use one or more test prostheses designed to enable measurements to be taken inside the patient's joint, those measurements then making it possible to configure the final prosthesis before said final prostheses is implanted.
Naturally, the use of such prior tests tends to increase the length of the surgical operation, and the trauma suffered by the patient, while also consuming a relatively large quantity of surgical equipment, and in particular a relatively large quantity of batches of test implants.